The Charging of Accumulators.

Progress, Volume II, Issue 5, 1 March 1907, Page 168

The Charging of Accumulators.

Our correspondent " Chauffeur " having put a question asking for information about the charging of accumulators, we have much pleasure in placing the following at his disposal and that of others who may want this useful information. The successful running of the motor will depend to a large extent upon the condition of the accumulator ; an imperfectly charged one will not produce a good spark. Most accumulators supplied for motor-cycles may be relied to run 800 miles before they require charging again. The best test to apply to an accumulator to see if it retains a charge is to place either a small four-volt incandescent lamp across the terminals, or connect the battery up to a voltmeter If the accumulator is charged, the lamp will glow brightly and remain so as long as it is connected ; if the accumulator is nearly exhausted, the lamp will only appear a dull red. A fully charged battery will show 4.2 volts, or just over two volts for each cell. Most riders have not got the necessary appliances for charging, and the usual method is to send the cells to an electrician and get it done ; the cost is very small. If the electric light is fitted in the house or shop — and providing it is continuous current — the accumulator can be readily charged. But it is only necessary to take the cover off one of the switches controlling a group of two or three lights, put the handle in the off position and find out which is the positive terminal. To do this, connect two lengths of insulated wire (bell- wire will serve), one to each connection of the switch. Clean the other ends of the wire bright and hold them apart in a glass of slightly acid water. The wire connected with the negative pole of the switch will give off bubbles of gas It is only necessary to join this wire to the black terminal, and the other wire to the red terminal of the accumulator, and leave on for about eight hours. The lamps will remain alight and with no appreciable loss of brilliancy. It is important to note that the handle of the switch remains off during the charging. When fully charged the accumulator will give off gas freely, and the liquid becomes a grey colour. The voltage will also rise to nearly 4.5. Charging from a lamp holder. — Instead of tapping the current at the switch it is often more convenient to connect the accumulator up to a lamp holder and charge it while the light is on. The method is simple. It is only necessary to purchase from an electrical fittings depot a simple holder, a fitting known as an " adapter," and a couple of yards of flexible conductor The adapter and lamp holder require to be wired The adapter is fitted into the

main lamp holder, and the lamp is inserted in the new holder. It only remains to find out which are the positive and negative ends of the wire, and connect up to the accumulator as before described. The lamp used would be either an 8, 16, 32, or 50 c.p , according to the size of the accumulator and the voltage of the lighting circuit. Charging from a dynamo — A good deal of misunderstanding sometimes arises as to the proper way to connect up an accumulator to the wires from a dynamo machine. The correct way is to connect the lamps across the wires, the accumulator being placed in the circuit between one of the brushes and one side of the wiring. According to the number of lamps in circuit will depend the amount of current in amperes that will pass through the cells. The current that each lamp will pass depends on its candle power and voltage. Bichromate battery — A perfectly satisfactory method of charging ignition accumulators at home is to rig up a two- fluid bichromate battery. One type is known as the " Fuller " battery. It consists of four glass or earthenware jars, and in each of these is placed a circular porous pot. Then placed in each outer jar are two carbon battery plates, and in the porous pot a thick zinc rod or plate, that has been previously amalgamated with some mercury. The outer ]ar is filled with a strong solution of 4 oz. chromic acid, water 16 oz., and 10 oz. sulphuric acid added The porous pot is filled with dilute sulphuric acid, one part to eight of water. The plates must be connected carbon to zinc, with insulated wire and joined up to the accumulators. An ammeter should if possible be placed in the circuit to see that no excess of charging current is passing ; if so, it will be necessary to place about 20 in. of No 20s German-silver wire in the circuit, and adjust it to the right length to give the correct charging current The battery will charge up a twelve-ampere-hour accumulator three times without the solutions being renewed, but it is important to see that the zincs are removed from the acid when not m use. The capacity of the outer jar should not be less than three pints The supplies can be obtained from any dealer in electrical fittings, or the battery complete can be purchased from one of the large motor accessories depots.